Half Moon Bay South Draft Plan #3

Transcription

1 Half Moon Bay South Draft Plan #3 SERVICING REPORT Prepared for: Mattamy Homes Ltd. Prepared by: Stantec Consulting Ltd.

2 Sign-off Sheet This document entitled Half Moon Bay South Draft Plan #3 was prepared by Stantec Consulting Ltd. for the account of Mattamy Homes Ltd. The material in it reflects Stantec s best judgment in light of the information available to it at the time of preparation. Any use which a third party makes of this report, or any reliance on or decisions made based on it, are the responsibilities of such third parties. Stantec Consulting Ltd. accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. Prepared by (signature) Dustin Thiffault, P.Eng. Reviewed by (signature) Peter Moroz, P.Eng., MBA

3 Table of Contents 1.0 INTRODUCTION OBJECTIVE PROPOSED PHASING OF OVERALL SITE BACKGROUND EXISTING CONDITIONS WATER SUPPLY SERVICING BACKGROUND ALLOWABLE PRESSURES GROUND ELEVATIONS EXISTING & PROPOSED WATERMAIN NETWORK BOUNDARY CONDITIONS WATER DEMAND HYDRAULIC MODEL RESULTS Average Day Peak Hour Maximum Day + Fire Flow Results SUMMARY OF FINDINGS STORM DRAINAGE OVERVIEW CRITERIA AND CONSTRAINTS Criteria Site Constraints PRELIMINARY STORMWATER MANAGEMENT PLAN Ultimate Conditions Ultimate Condition Hydrology Ultimate Condition Hydraulic Grade Line Analysis CONCLUSIONS AND RECOMMENDATIONS (SWM) SANITARY DRAINAGE SANITARY SEWER PROPOSED SANITARY SEWERS DESIGN CRITERIA GEOTECHNICAL INVESTIGATION GRADING AND DRAINAGE UTILITIES HYDRO ENBRIDGE GAS TELECOMMUNICATIONS dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx i

4 10.0 EROSION AND SEDIMENT CONTROL DURING CONSTRUCTION DITCHES Diversion Ditches Discharge Ditches TEMPORARY SEDIMENTATION BASINS DEWATERING GEOTEXTILE BAGS EROSION CONTROL MONITORING CONCLUSION STORMWATER SERVICING SANITARY SERVICING WATER SERVICING GRADING UTILITIES LIST OF TABLES Table 1: Development Areas Table 2: City of Ottawa Water Distribution Guidelines for Hazen-Willams "C" Coefficient Table 3: Boundary Conditions Table 4: AVDY Pressure Results (Nodes) Table 5: AVDY Pressure Results (Links) Table 6: PKHR Pressure Results (Nodes) Table 7: PKHR Pressure Results (Links) Table 8: MXDY + FF Results (13,000L/min Boundary Condition) Table 9: MXDY + FF Results (12,000L/min Boundary Condition) Table 10: MXDY + FF Results (10,000L/min Boundary Condition) Table 11: HMBS- Draft Plan #3 Major and Minor System 5 Year Storm Results Table 12: HMBS Draft Plan #2 Major and Minor System 100 Year Storm Results Table 13: 100 Year Total Flow Depth Comparison Table 14: 3hr Chicago Hydraulic Grade Line Results LIST OF FIGURES Figure 1: Key Plan Figure 2: Location of Proposed Development Figure 3: Proposed Servicing Plan (Proposed Diameters are in mm) Figure 4: Location of Boundary Conditions Figure 5: Ground Elevations (m) of Nodes Figure 6: Junction IDs Figure 7: Pipe IDs Figure 8: AVDY Pressure Results (m) Figure 9: PKHR Pressure Results (m) Figure 10: MXDY + FF Available Fire Flows (L/s) (10,000L/min Boundary Condition) Figure 11: MXDY + FF Available Fire Flows (m) (12,000L/min Boundary Condition) Figure 12: MXDY + FF Available Fire Flows (L/s) (13,000L/min Boundary Condition) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx ii

5 LIST OF APPENDICES APPENDIX A STORMWATER MANAGEMENT CALCULATIONS... A.1 A.1 Parameter Summary and Calculations (DDSWMM)... A.2 A.2 OUTPUT SUMMARY (DDSWMM)... A.3 A.3 OUTPUT SUMMARY (XPSWMM)... A.4 A.4 Storm Sewer Design Sheets... A.5 A.5 JFSA Correspondence... A.6 APPENDIX B APPENDIX C APPENDIX D APPENDIX E APPENDIX F SANITARY SEWER DESIGN SHEETS... B.7 POTABLE WATER HYDRAULIC ANALYSIS (RESULTS)... C.8 GEOTECHNICAL REPORT EXCERPTS... D.9 CITY CORRESPONDENCE... E.10 FIGURES AND DRAWINGS... F.11 dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx iii

6 Introduction 1.0 Introduction This servicing report is prepared in support of Draft Plan #3 of the Mattamy Homes Ltd. Half Moon Bay South development. The proposed development is located west of Greenbank Road, approximately 500 m south of Cambrian Road within the Barrhaven South community in the City of Ottawa (see Figure 1: Key Plan). Draft Plan #3 lands are located to the immediate southwest of the approved Draft Plan #2. The proposed development comprises approximately 23.8 ha of land and consists of mixed residential development, two school blocks, and park land. An illustration of the site location is shown below: Figure 1: Key Plan dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 1.1

7 Introduction 1.1 OBJECTIVE This Servicing report has been prepared to present a servicing scheme that is free of conflicts in the proposed draft plan as well as in the overall development, and utilizes the existing infrastructure constructed as a result of Draft Plan #2 via infrastructure as outlined in the different background studies. Specific elements and potential development constraints to be addressed are as follows: Address infrastructure needs in sufficient detail to assist in the preparation of detailed design drawings Prepared conceptual Grade Control Plan Storm Sewer Servicing Define major and minor conveyance systems in conjunction with the grade control plan Determine the stormwater management (SWM) storage requirements based on the criteria provided for the development Wastewater Servicing Define and size the sanitary collection system Water Servicing Define and size the internal water system with connection to the existing 305 mm dia. watermain on River Mist Road and the existing 300mm dia. watermain within existing development lands east of Greenbank Road (intersection of Dundonald & Blackleaf Drive) Define buildout conditions relating to construction of additional watermain connection on realignment of Greenbank Road Watermain servicing for the development is to be able to provide average day and maximum day (incl. peak hour) demands (i.e. non-emergency conditions) at pressures within the acceptable range of 40 to 80 psi (276 to 550 kpa) in occupied areas Under fire flow (emergency) conditions, the water distribution system is to maintain a minimum pressure greater than 20 psi (140 kpa) Grading, drainage and services for the area will be designed in accordance with the City of Ottawa guidelines. The accompanying drawings included in Appendix F Figures and Drawings illustrate the internal servicing scheme for the overall site. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 1.2

8 Introduction 1.2 PROPOSED PHASING OF OVERALL SITE Draft Plan #3 is part of the larger overall development, which has been phased to allow for sequencing of the development. Currently, the project identifies three draft plans proposed for the development, with a future draft plan to encompass Mattamy owned lands not included as part of the CDP to the southwest. The attached figure (Figure 5.0: Phasing in Appendix F) illustrates the location and configuration of the Draft Plan #3 area within the overall development and was taken into account in the overall servicing analysis. Table 1 below identifies the development areas within each draft plan: Table 1: Development Areas Phase Draft Plan # Draft Plan # Draft Plan # Future Draft Plan 5.62 Area (ha) Since most of the servicing/utility outlets and connecting roads are located to the north and east of the site, development will logically proceed from east to west and from north to south as the extension of servicing and roads advances through the site, and, in the case of the secondary school block tributary to the Clarke Pond, as downstream outlets become available. Presently, draft plan limits have been set with respect to minor and major storm boundaries with minor adjustments to accommodate the road connectivity network. With the exception of the aforementioned school block, the minor drainage system of draft plan #3 is to drain to the existing Corrigan and Todd Ponds. The major system of draft plan #3 drains in its majority to the existing Todd Pond. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 1.3

9 Background 2.0 Background The Barrhaven South Community Design Plan (CDP) was approved by Ottawa City Council based on the following background studies that demonstrated the serviceability of the proposed urban lands: Transportation Master Plan (Draft), Delcan Corporation, April 2006 Barrhaven South Community Design Plan, Fotenn Consultants Inc., June 1, 2006 Barrhaven South Master Servicing Study (MSS), Stantec Consulting Ltd., File No , June 26, 2007 Jock River Reach 1 Subwatershed Study, Stantec Consulting Ltd., June 2007 Subsequently, the Servicing Brief for Half Moon Bay Development Phase One for Mattamy Homes in the City of Ottawa was prepared by DSEL in April 2008, which included some deviations from the Barrhaven South MSS completed by Stantec in June Specifically, the storm drainage areas tributary to the Todd Pond and the Clarke Pond were modified, the configuration of the Todd Pond was altered, the minor system capturing rates and required major system storage for the areas tributary to the Todd Pond were changed, and the configuration of the sanitary and watermain systems was modified. Additionally, sizing for the trunk sanitary and watermain along Greenbank Road has been increased to accommodate future development. Similarly, the Corrigan Stormwater Management Facility - Stormwater Management Report and Design Brief was prepared by IBI Group in July The Corrigan stormwater management Report outlines the SWM criteria for the lands tributary to the Corrigan Pond. In August 2014, J.F. Sabourin & Associates (JFSA) presented a revised Todd pond model as part of their Model Keeper Analysis for Todd Pond making use of the dual routing procedure for DDSWMM outlined in Technical Bulletin ISDTB The resultant increase in storage provided in existing roadways permitted expanded Todd pond drainage boundaries also outlined in the JFSA Model Keeper Analysis. It is the intent of the proposed servicing scheme to make use of all available drainage area allocated to the Todd pond to limit requirements for a minor system sewer to the Clarke Pond to service Half Moon Bay South. As a result of the above mentioned changes, the Barrhaven South MSS will be subject to an update in the very near future and as such, the design assumptions outlined in this report will be revisited once the update to the Barrhaven South MSS is completed. The following studies and guidelines were also referenced in the preparation of this servicing brief: City of Ottawa Sewer Design Guidelines, City of Ottawa, October 2012 Servicing Brief for Half Moon Bay Development Phase One for Mattamy Homes in the City of Ottawa, DSEL, April 2008 dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 2.4

10 Background Preliminary Geotechnical Investigation Report Proposed Residential Subdivision, Half Moon Bay Phase III Greenbank Road, Jacques Whitford, September 12, 2008 Barrhaven South CDP Potable Water Hydraulic Analysis Addendum New Pressure Zone 3C Boundary, Memo from Kevin Alemany (Stantec) to Roman Diduch (City of Ottawa), File no , June 1, 2009 Corrigan Stormwater Management Facility - Stormwater Management Report and Design Brief, IBI Group, 2010 Stormwater Management Report for Phases 1, 2A, 2B, 2C, 3, 5 and 6 of the Half Moon Bay Development (Barrhaven South) of the Mattamy Homes Subdivision, J. F. Sabourin and Associates Inc., June 2010 Ottawa Design Guidelines Water Distribution, Infrastructure Services Department, City of Ottawa, First Edition, July 2010 Stormwater Management Strategy for the Meadows in Half Moon Bay and Half Moon Bay South Developments, IBI Group, July 2010 Noise and Dust Assessment Proposed Subdivision Development, Parts of Lots 8 and 9, Concession 3, Ottawa, Ontario, Golder Associates, September 2010 Half Moon Bay South Draft Plan Servicing Report, Stantec, November 2010 Half Moon Bay South Phase 1A Servicing Report, Stantec, March 2011 Correspondence on HMBS Drainage Divide to Future Clarke Pond, Corrigan Pond and Todd Pond, J. F. Sabourin and Associates Inc., April 18, 2011 Geotechnical Investigation Report Proposed Residential Subdivision, Half Moon Bay Phase 1A Greenbank Road, Stantec Consulting, November 2011 Half Moon Bay Subdivision Draft Plan Redline Engineering Rationale, Stantec, February Model Keeper Analysis Reassessment of Existing System Capacity, J. F. Sabourin and Associates Inc., August 29, Half Moon Bay South Phase 2 and 3 Stormwater Management Report, Stantec, February Half Moon Bay South Draft Plan #2 Detailed Design, Servicing Report, Stantec, August dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 2.5

11 Existing Conditions 3.0 Existing Conditions The site has been previously designated for development (currently zoned DR) and is part of the City of Ottawa s official plan. The site lies within Jock River Watershed and outlets to three independent SWM facilities, Corrigan Pond, Todd Pond, and Clarke Pond. Two of the facilities, Corrigan and Todd Pond, have been constructed and the site is included in the existing Certificate of Approval (C of A) for those facilities. Clarke Pond is yet to be designed and approved. A portion of the site designated Draft Plans #1 and #2 have been designed, approved and/or constructed encompassing the north east half of the site. The existing site is intercepted by the former Todd Municipal Drain and Clarke Municipal Drain. The drains were abandoned by City Council in 2007 to serve as local drainage ditches for rural area. A separate permit for compensation and filling of the ditches was received from the Department of Fisheries and Oceans (DFO). A temporary dry pond (See Fig 2.0 in Appendix F) will be required for overland flows from external rural areas from the south until such time as that area is developed and flows from lands to the south diverted to a future permanent SWM facility off site. Based on discussions with the Rideau Valley Conservation Authority (RVCA), it was established that a standard application for Alteration of a Watercourse to re-route and infill the existing watercourses, including all associated erosion and sediment control works, would be required under Alteration to Watercourses. This application was submitted and approval was granted on February 14, 2011 (File #: RV5-3510T); the approval letter is included in Appendix E. A Permit to Take Water (reference no K7RQV) for this phase of development was obtained from the Ministry of the Environment (MOE) on January 16, The permit is valid from October 1, 2010 to September 30, The area is labeled as Area 3 & 4 HMN Phase 3. Water quality monitoring locations have been identified in the permit. Based on consultations with the local MOE office, a C of A application was submitted to modify the existing C of A for the Todd SWM Facility, to include the proposed interim erosion control works, covering: the temporary siltation control ponds, interim drainage control pond for treatment of storm water and ground water during construction of the subdivision, temporary diversion of the East Clarke Drain to the West Clarke Drain, and silt fence barrier system and straw bale barrier system during construction. The application was approved on April 29, 2011, (reference no GBHW6) and is included in Appendix E. Upon detailed design, the standard ECA requirements will apply for the sewer and trunk extensions and networks within the subdivision, which will be covered under the transfer of review program. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 3.6

12 Water Supply Servicing 4.0 Water Supply Servicing 4.1 BACKGROUND The proposed development is located along the western side of Greenbank Road mid-way between Cambrian Road (to the north), and Barnsdale Road (to the south), as shown in Figure 2: Location of Proposed Development. This residential development will include 159 single family home lots, 105 townhomes (up to three stories), two school blocks (5.83 and 2.77ha) and a residential park areas (3.1 and 0.91 ha). It is part of the existing Zone BARR (Barrhaven) of the City of Ottawa water distribution system. The area will be converted to Zone 3C by Currently, this zone is fed by the Barrhaven Pumping Station. This submission includes the servicing analysis and recommendations based on estimated boundary conditions corresponding to current pressure zone configurations. The boundary conditions were obtained from the City of Ottawa for the previous phase of development. Figure 2: Location of Proposed Development SITE BARR PRESSURE ZONE dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.7

13 Water Supply Servicing See Figure 3: Proposed Servicing Plan (Proposed Diameters are in mm) for the proposed servicing plan for Plan #3 which includes tying into the existing Plan #1 and #2 development and future roads to the west and south of the development. These connections will ensure adequate looping of the proposed network for Plan #3. Watermains shown outside of the draft plan boundary exist currently. Figure 3: Proposed Servicing Plan (Proposed Diameters are in mm) 155mm Diameter 204mm Diameter 297mm Diameter Draft Plan Boundary Boundary Conditions were applied at existing connection locations within Draft Plan #1 along Greenbank Road, as well as at River Mist Road and Pennant Avenue, and were simulated in the modeling software as a series of fixed-head reservoirs. See Figure 4: Location of Boundary Conditions. The boundary condition #4 was not supplied by the City of Ottawa, and was instead interpolated from boundary conditions #3 and #5. The connection point west of boundary condition #1 on Grand Canal is not currently constructed, and has been considered as a dead end for the purposes of this analysis. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.8

14 Water Supply Servicing Figure 4: Location of Boundary Conditions #3 #2 #1 #4 #5 #6 #7 4.2 ALLOWABLE PRESSURES The City of Ottawa Water Distribution Design Guidelines state that the design objective for system pressures under normal demand conditions (i.e. average day, maximum day and peak hour) shall remain between the range of 275 to 552 kpa (40 to 80 psi) at the ground elevation in the streets (i.e. at hydrant level) for typical one and two-story buildings. Under emergency fire flow conditions, the minimum pressure in the distribution system is allowed to drop to 140 kpa (20 psi). 4.3 GROUND ELEVATIONS The proposed ground elevations of the proposed development range from approximately 97.8m to 101.7m. The elevations shown on Figure 5: Ground Elevations (m) of Nodes were taken from the proposed grading plan and assigned to the nodes in the hydraulic model. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.9

15 Water Supply Servicing Figure 5: Ground Elevations (m) of Nodes 155mm Diameter 204mm Diameter 297mm Diameter Draft Plan Boundary Ground Elev. (m) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.10

16 Water Supply Servicing 4.4 EXISTING & PROPOSED WATERMAIN NETWORK Following the completion of this project, potable water supply will be provided through the existing Plan #1 and #2 development, along with larger diameter 406mm and 305mm watermains on the future roads to the west and south of the Draft Plan #3 development respectively. All watermains to be constructed as part of the Draft Plan #3 development will be installed as a single development phase. Watermains have been sized on the basis of providing the minimum sizing necessary to meet the level of service requirements. New watermains were added to the hydraulic model within the proposed development area in order to simulate the proposed distribution system. Hazen-Williams coefficients ( C-Factors ) were applied to the new watermains in accordance with the City of Ottawa s Water Distribution Design Guidelines (See Table 2). The entirety of Draft Plan #3 will be constructed as a single phase, and as such, no temporary requirements for construction of watermain to rectify quality concerns or inadequate fire flows resulting from partial site development have been identified. Looping for the ultimate site buildout, however, requires a temporary 300mm watermain be installed within an easement at the south of the school property at the site s southern boundary until such time as further development to the south may occur. Table 2: City of Ottawa Water Distribution Guidelines for Hazen-Willams "C" Coefficient Pipe Diameter (mm) C-Factor 50 to to to Over BOUNDARY CONDITIONS The hydraulic model used for this analysis was created by Stantec. The boundary conditions for the model were provided by the City of Ottawa and interpolated with respect to the assumed fire flow demand to be analyzed. Fixed head reservoirs simulating the boundary conditions were placed along Greenbank Road, as well as at River Mist Road and Pennant Avenue as shown in Figure 4: Location of Boundary Conditions. Boundary conditions account for future pressure zone reconfiguration to Zone 3C, and represent critical design conditions considering both pre and post zone reconfiguration scenarios. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.11

17 Water Supply Servicing Table 3: Boundary Conditions Node: Average Day (AVDY): Peak Hour (PKHR): Max Day + Fire Flow (MXDY + FF): (13,000L/min) (Interpolated) Max Day + Fire Flow (MXDY + FF): (12,000L/min) (Interpolated) Max Day + Fire Flow (MXDY + FF): (10,000L/min) (Interpolated) 4.6 WATER DEMAND Water demands for the development were estimated using the City of Ottawa s Water Distribution Design Guidelines. The estimated household size of an average townhome is 2.7 persons and the estimated household size of an average single family home is 3.4 persons. Therefore, the total projected population for the proposed residential development will be approximately 824 upon completion of the development. For residential developments, the average day per capita water demand is 350 L/(cap*d). Based on these design guidelines, it is estimated that this development will generate an average day residential demand of 3.34 L/s. The distribution of demands was based on the proximity of the buildings to the relevant model node. For maximum daily demand and peak hour demand, residential demands were multiplied by a factor of 2.5 times average day demand, and 2.2 times the maximum daily demand, respectively. See Appendix C for full summary of the demand allocation. 4.7 HYDRAULIC MODEL RESULTS The software package used to carry out the analysis was H2OMAP Water by Innovyze. The model was tested under three different domestic demand conditions: average day (AVDY), peak hour (PKHR) and maximum day plus fire flow (MXDY + FF) under current pressure zone configurations. Figure 6: Junction IDs and Figure 7: Pipe IDs provide the IDs of each of the proposed junctions and pipes input into the hydraulic model. These IDs are used to present the results in tabular format in the following sections. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.12

18 Water Supply Servicing Figure 6: Junction IDs Draft Plan Boundary 10 Junction ID dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.13

19 Water Supply Servicing Figure 7: Pipe IDs Draft Plan Boundary 1000 Pipe ID dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.14

20 Water Supply Servicing Average Day Spreadsheets within Appendix C present the model output results for the average day demand analysis. As shown, the typical operating pressures are anticipated to range between 632 kpa (91.7 psi) and 681 kpa (98.8 psi) based on the local ground elevations and pipe hydraulic conditions. The range of anticipated operating pressures exceeds the recommended pressure range of 275 kpa to 552 kpa (40 to 80 psi), as recommended by the City of Ottawa s Water Distribution Design Guidelines. Per the Ontario Plumbing Code, pressure reducing valves (PRV s) are required for all services (pressures higher than 552 kpa (80 psi)). Figure 8: AVDY Pressure Results (m) Draft Plan Boundary AVDY Pressure (m) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.15

21 Water Supply Servicing Table 4: AVDY Pressure Results (Nodes) ID Demand (L/s) Elevation (m) Head (m) Pressure (m) Pressure (psi) Pressure (kpa) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.16

22 Water Supply Servicing Table 5: AVDY Pressure Results (Links) ID From Node To Node Length (m) Diameter (mm) Roughness Flow (L/s) Velocity (m/s) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.17

23 Water Supply Servicing Peak Hour Spreadsheets within Appendix C present the model output results for the peak hour demand analysis. As shown, the typical operating pressures are anticipated to range between 280 kpa (40.6 psi) and 329 kpa (47.7 psi) based on the local ground elevations and pipe hydraulic conditions. The resultant pressures are thus within the allowable pressure range of 275 kpa to 552 kpa (40 to 80 psi), as recommended by the City of Ottawa s Water Distribution Design Guidelines. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.18

24 Water Supply Servicing Figure 9: PKHR Pressure Results (m) Draft Plan Boundary PKHR Pressure (m) Table 6: PKHR Pressure Results (Nodes) ID Demand (L/s) Elevation (m) Head (m) Pressure (m) Pressure (psi) Pressure (kpa) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.19

25 Water Supply Servicing Table 7: PKHR Pressure Results (Links) ID From Node To Node Length (m) Diameter (mm) Roughness Flow (L/s) Velocity (m/s) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.20

26 Water Supply Servicing dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.21

27 Water Supply Servicing Maximum Day + Fire Flow Results The City of Ottawa s design guidelines for water distribution systems require a minimum pressure of 140 kpa (20 psi) to be maintained at all points in the distribution system under a condition of maximum day and fire flow demand. For the purposes of this analysis, a fire flow of L/s (10,000 L/min) was used for single family homes and townhome units per the cap on fire flows indicated in the recent technical bulletin by the City of Ottawa dated May 27, Required fire flows of between L/s (12,000 L/min) and L/s (13,000 L/min) were assumed for the back-to-back townhome complexes, and will be reassessed at the detailed design stage. Fire separations will be considered at the detailed design stage for the proposed back-to-back unit complexes. A fire flow analysis was carried out using the hydraulic model to determine the anticipated amount of flow that could be provided at each of the nodes in the proposed development under maximum day demands while still maintaining a residual pressure of 140 kpa (20 psi). This was accomplished using a steady-state maximum day demand scenario along with the automated fire flow simulation feature of the software. The fire flow results presented in Appendix C show that fire flows greater than the minimum required are available at all locations within the proposed development at their relevant boundary conditions. All nodes resulted with residual pressures in excess of 20 psi. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.22

28 Water Supply Servicing Figure 10: MXDY + FF Available Fire Flows (L/s) (10,000L/min Boundary Condition) Draft Plan Boundary Avail. Fire Flows (L/s) Figure 11: MXDY + FF Available Fire Flows (m) (12,000L/min Boundary Condition) Draft Plan Boundary Avail. Fire Flows (L/s) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.23

29 Water Supply Servicing Figure 12: MXDY + FF Available Fire Flows (L/s) (13,000L/min Boundary Condition) Draft Plan Boundary Avail. Fire Flows (L/s) ID Static Demand (L/s) Table 8: MXDY + FF Results (13,000L/min Boundary Condition) Static Pressure (m) Static Head (m) Fire-Flow Demand (L/s) Residual Pressure (m) Pressure (psi) Pressure (kpa) Available Flow at Hydrant (L/s) Available Flow Pressure (m) ID Static Demand (L/s) Table 9: MXDY + FF Results (12,000L/min Boundary Condition) Static Pressure (m) Static Head (m) Fire-Flow Demand (L/s) Residual Pressure (m) Pressure (psi) Pressure (kpa) Available Flow at Hydrant (L/s) Available Flow Pressure (m) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.24

30 Water Supply Servicing ID Static Demand (L/s) Table 10: MXDY + FF Results (10,000L/min Boundary Condition) Static Pressure (m) Static Head (m) Fire-Flow Demand (L/s) Residual Pressure (m) Pressure (psi) Pressure (kpa) Available Flow at Hydrant (L/s) Available Flow Pressure (m) dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.25

31 Water Supply Servicing 4.8 SUMMARY OF FINDINGS The proposed servicing in this development will provide sufficient capacity to sustain both the required domestic demands and emergency fire flows. Based on computer modeling results, fire flow demands are available at all nodes for this development based on the watermain alignment and sizing shown in Figure 3 without system pressures dropping below 20 psi (140 kpa). The minimum pressure found within the model output results, 280 kpa (40.6 psi), is within the recommended design guidelines for minimum pressure for one and two story units. However, the maximum pressure achieved according to the model output results, 681 kpa (98.8 psi), is not within the recommended design guidelines for maximum pressures and therefore, pressure reducing valves are recommended for all proposed units within the Draft Plan in order to satisfy the design guidelines. This distribution system contains adequate looping and satisfies the reliability requirement for looping from the City of Ottawa. dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 4.26

32 Storm Drainage 5.0 Storm Drainage 5.1 OVERVIEW A Stormwater Management Report is being submitted concurrently with this report, under separate cover. For more details on the SWM design, please refer to the report entitled Half Moon Bay South Draft Plan #3, Barrhaven South, City of Ottawa, Stormwater Management Report, Stantec Consulting Ltd., dated. In order to allow the Meadows in Half Moon Bay (Tamarack lands north of the site) and the Half Moon Bay South (Mattamy lands) development to proceed prior to the update to the Barrhaven South MSS, J. F. Sabourin and Associates (JFSA) undertook an analysis in August 2014 to evaluate the performance of the existing Todd pond and proposed Clarke pond systems by combining several separate models developed by JFSA (Half Moon Bay subdivision), IBI (Meadows in Half Moon Bay) and Stantec (Half Moon Bay South). The analysis has been subsequently revised every time there are changes to the Meadows in Half Moon Bay and/or the Half Moon Bay South developments to assess impacts on the Todd and Clarke Pond storm systems. The results of the latest analyses are summarized in Appendix A CRITERIA AND CONSTRAINTS The following section discusses the criteria and constraints influencing the design of Draft Plan #3 (DP3) of the Half Moon Bay South (HMBS) development Criteria Criteria were established through review of the background documentation, supplemented with current design practices outlined by the City of Ottawa Sewer Design Guidelines (City of Ottawa, October 2012) and the City of Ottawa s Technical Memo (City of Ottawa, January 2012). Use of the dual drainage principle Maximum 100 year flow depth of 0.30 m in road sags Standing water depths at road sags not to cause surface flooding on any building or structure Rear-yard storage not to be included in stormwater management (SWM) calculations Use of standard self-cleansing inlet-control devices where possible Ensure that 100 year overland flows from the proposed HMBS development tributary to River Mist Road are captured into the minor system prior to entering the adjacent Meadows in Half Moon Bay development to the north dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 5.27

33 Storm Drainage Maximum peak release rate from the HMBS development to the Corrigan pond at MH521 (existing manhole in phase 1A) to be 1,466 L/s as obtained from the 100 year XP- SWMM model included in the SWM Report of Phase 1A of the HMBS development (Stantec, July 2011) 100 year major flows entering Phase 1A at Andre Audet Avenue to be less than 1.48 m 3 /s as obtained from the 100 year DDSWMM model included in the SWM Report of Phase 1A of the HMBS development (Stantec, July 2011) Proposed schools in Draft Plan #2 of the HMBS development to store post development 100 year peak flows on site while restricting minor system flows to 120 L/s/ha 100 year hydraulic grade line (HGL) to be a minimum of 0.30 m below building foundation footings (3hr Chicago Storm) for existing and approved phases and a minimum of 2.5 m below proposed road grades across future development areas where possible Size storm sewers to convey the 5 year storm event under free-flow conditions using 2004 City of Ottawa I-D-F parameters with the exception of the trunk sewer along River Mist Road to the Todd pond, and the trunk sewer along Dundonald Drive to the future Clarke Pond which have been sized in XP-SWMM to capture and convey the 100 year post development flows, while meeting the Under Side of Footing (USF) / proposed road grade - HGL clearance criteria across the site Subdrains required in swales where longitudinal gradient is less than 1.5% Account for tributary external drainage through the system Provide adequate emergency overflow conveyance off-site Quality control is provided in the downstream Barrhaven South Todd and Corrigan Ponds Site Constraints As shown in the background documents, the HMBS development is within an area of Barrhaven South that has three separate outlets for both minor and major systems. The proposed DP3 of the HMBS development has several storm sewer outlets. One storm outlet is proposed to the Corrigan Pond via an existing 525mm dia. storm sewer that directs runoff to the trunk sewer along Andre Audet Avenue through phase 2 towards the storm system in phase 1A of the HMBS development, which in turn ultimately discharges into an existing 1950 mm dia. trunk sewer on the existing Greenbank Road. The minor system allowable release rate to the existing MH521 at the Phase 1A boundary towards the Corrigan Pond is 1,466 L/s. Three storm outlets in DP3 will direct runoff to the Todd Pond storm system running north along River Mist Road towards the storm system across the Meadows in Half Moon Bay development (see Drawing SD-1). dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 5.28

34 Storm Drainage 5.3 PRELIMINARY STORMWATER MANAGEMENT PLAN The following sections describe the stormwater management (SWM) plan for Draft Plan #3 (DP3) of the HMBS development in the context of the background documents and available governing criteria Draft Plan #3 Buildout Conditions The proposed DP3 of the MHBS development (the site) will comprise a combination of townhouse units, terrace homes and single-family residential lots, two schools, park land and associated transportation and servicing infrastructure. The proposed site is designed using the dual drainage principle, whereby the minor (pipe) system is designed to convey the peak rate of runoff from the 5 year design storm (or equivalent flow rate), and runoff from larger events is conveyed by both minor (pipe) and major (overland) channels such as roadways and walkways safely off site. A combination of vertical orifices and IPEX inlet control devices (ICDs) are specified for most street and rear yard catchbasins to limit the inflow to the minor system and thus control the hydraulic grade line from surcharging storm sewers into basements during major storms and to meet the target release rates from the site. Solid covers are proposed for all manholes located in ponding areas to limit inflows to the minor system to that of the ICD. As recommended by the Ottawa Sewer Design Guidelines, no storage will be accounted for in the rear yards. Drawing SD-1 outlines the proposed drainage areas. Major system runoff from the proposed DP3 development will be directed to two separate outlets. A major system outlet will be provided overland through Andre Audet Avenue which will direct major flows to Regatta Avenue at the Meadows in Half Moon Bay development while a second major system outlet will be provided through the storm trunk sewer along River Mist Road which conveys minor and major system flows to the Todd Pond. Several unrestricted curb inlets have been installed along the section of River Mist Road within Phase 1A in order to capture the 100 year major flows from the portion of the HMBS development tributary to the River Mist Road outlet, while meeting the USF clearance criteria across the site. A temporary dry pond is proposed to attenuate flows from external rural tributary areas (see Appendix A.5) per the results of the Barrhaven South Master Servicing Study. Flows will be attenuated to 350L/s in the 100yr storm event scenario. Pond sizing is to be completed at the detailed design stage Hydrology A comprehensive hydrologic modeling exercise was completed with DDSWMM, accounting for the estimated major and minor flows to evaluate the response of the storm sewer infrastructure and the site s major systems. Two DDSWMM models were created; one for the minor system to the Corrigan pond and major system to Andre Audet Avenue at the boundary of Phase 1A and dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 5.29

35 Storm Drainage a second model for the minor system to the Todd Pond and major system to River Mist Road. The DDSWMM models incorporate subcatchments within the proposed DP3 area, the approved Phases 2, 3 and part of the existing Phase 1A, and lumped drainage areas for future development lands southwest of the HMBS development tributary to the Todd Pond. Catchments within the approved phases of the development have been included in order to assess any impacts to the existing major and minor systems. Drawing SD-1 shows the drainage catchments in the HMBS development along with the preliminary storm servicing infrastructure Hydrologic Parameters and Assumptions Surface storage estimates for the subcatchments within the proposed DP3 and the approved and existing phases of the HMBS development were based on the grading plan designs, while the approximate surface storage available in the lumped catchments within future areas of the HMBS development was assumed based on the preliminary proposed road grade slope and type of road. The following assumptions were applied to the DDSWMM models: Hydrologic parameters as per Barrhaven South MSS (Stantec, 2007), including Horton infiltration, Manning s n and depression storage values (see Appendix A1) 3hr Chicago Storm distribution as outlined in the Barrhaven South MSS (Stantec, 2007) Major system to be assessed during the July 1st, 1979 historical storm and during the 100 year design storm increased by 20% Impervious areas were measured in several representative catchments based on the type of units in the catchment (single, townhouse, etc.) and whether they were road or rear yard catchments. Impervious areas for these catchments were based on a maximum unit size based on lot setbacks and as such the impervious areas measured are considered conservative. The imperviousness values calculated were used in similar catchments across the site. Imperviousness values were converted to runoff coefficients for storm sewer sizing purposes using the relationship C = (Imp. x 0.7) Imperviousness values for rear yard catchments within the proposed DP3 were assumed to be 80% effective DDSWMM segment lengths defined from high-point to low-point where sags occur Subcatchment width equal to two times the average segment length for two-sided catchments, equal to one time the segment length for one-sided catchments, and equal to 225 times the area of the catchment for any other catchments Draft Plan #2 catchments were included in the model and the parameters used for these catchments (areas, length, width and inlet information) were obtained from the DDSWMM model included in the HMBS Draft Plan #2 SWM Report (Stantec, August 2014) Phase 2 & 3 catchments were included in the model and the parameters used for these catchments (areas, length, width and inlet information) were obtained from the dt w:\active\ _half_moon_bay_south_draft_plan\design\report\servicing report\ , dp3\rpt_ _srv.docx 5.30